No, the money you get back at closing is not taxable. The IRS has given guidance that commission refunds do not need to be reported as income. You can review an excerpt from the letter ruling below:
"In the present case, a payment or credit at closing from Taxpayer represents an adjustment to the purchase price of the home and generally is not includible in a purchaser’s gross income."
For more information, we suggest consulting with a CPA or other tax professional.